Which statement about the outer electrons of alkali metals is true?

Which statement about the outer electrons of alkali metals is true?

• A. Three electrons
• B. Eight electrons
• C. Five electrons
• D. One electron

Answer: (D)

One outer electron is what alkali metals have in their outermost shell. They sit in Group 1 of the periodic table, and their electron configuration ends with s1, meaning there is a single valence electron. That lone outer electron is what the atom tends to lose to form a +1 ion, which is why alkali metals are so reactive. Saying three, five, or eight outer electrons would imply a different group and different bonding behavior, so the correct description is that there is one electron in the outer shell.

One outer electron is what alkali metals have in their outermost shell. They sit in Group 1 of the periodic table, and their electron configuration ends with s1, meaning there is a single valence electron. That lone outer electron is what the atom tends to lose to form a +1 ion, which is why alkali metals are so reactive. Saying three, five, or eight outer electrons would imply a different group and different bonding behavior, so the correct description is that there is one electron in the outer shell.